Sign with changeable character plates

ABSTRACT

A framed backing panel is provided with opposed, vertically spaced groove means which respectively receive the upper and lower edges of character plates. The distance between the bases of the upper and lower groove means is sufficiently greater than the height of the character plates, that when any character plate is raised to abut the base of the upper groove, the lower edge of that character plate will clear the lip of the lower groove, whereupon the character plate may be removed from the sign. To prevent unauthorized removal of character plates, an unobtrusive locking strip is longitudinally removably disposed in the upper groove between the base and the upper edges of the character plates. Means may be provided to prevent removal of the locking strip. The panel frame is preferably T-slotted to provide a convenient fastener mount for mounting the sign.

[451 May 20, 1975 Barnes SIGN WITH CHANGEABLE CHARACTER PLATES [76] Inventor: Guy W. Barnes, 1005 S. 48th Ave.,

Yakima, Wash. 98902 [22] Filed: Sept. 10, 1971 [21] Appl. No.: 179,430

[52] US. Cl. 40/65; 40/140 [51] Int. Cl. G09f 11/30 [58] Field of Search 40/63 R, 64 R, 65, 17, 40/ 140, 142 R [56] References Cited UNITED STATES PATENTS 834,447 10/1906 Borgmann 40/140 X 1,359,510 11/1920 Kornicker 40/140 2,006,573 7/1935 lsenhour 40/63 R 2,287,423 6/1942 Hopp et al. 40/17 3,084,464 4/1963 Ladbury 40/63 R X 3,407,525 10/1968 Connell 40/140 3,531,884 10/1970 Adler 40/140 Primary ExaminerRobert W. Michell Assistant Examiner.lohn H. Wolff Attorney, Agent, or FirmCushman, Darby & Cushman I 5 7 ABSTRACT A framed backing panel is provided with opposed, vertically spaced groove means'which respectively receive the upper and lower edges of character plates. The distance between the bases of the upper and lower groove means is sufficiently greater than the height of the character plates, that when any character plate is raised to abut the base of the upper groove, the lower edge of that character plate will clear the lip of the lower groove, whereupon the character plate may be removed from the sign. To prevent unauthorized removal of character plates, an unobtrusive locking strip is longitudinally removably disposed in the upper groove between the base and the upper edges of thecharacter'plates. Means may be provided to prevent removal of the locking strip. The panel frame is preferably T-slotted to provide a convenient fastener mount for mounting the sign.

14 Claims, 10 Drawing Figures .LA---l- SIGN WITH CHANGEABLE CHARACTER PLATES BACKGROUND OF THE INVENTION A sign with removable character plates is shown in the U.S. patent of James P. Connell, U.S. Pat. No. 3,407,525, issued Oct. 29, 1968. With respect to FIG. 2 of that patent, the locking strip of the present invention would be longitudinally inserted in the space crossed by the lead line of the numeral 32.

When signs with movable character plates are mounted where they are accessible to people, and people have the opportunity, they steal and/or rearrange the character plates, because they have a basic inclination to do so. Many signs, in order to fulfill their intended roles must be displayed where, coincidentally, they are also vulnerable to peoples inclinations.

Accordingly, the present inventor, and others, have spent time trying to devise ways and means for foiling the attempts of unauthorized would-be sign changers.

Some previous efforts to lock changeable character plates in place on signs are disclosed in the following patents:

Patentee Patent No. Issue Date Holder 1,574,652 February 23, 1926 Gautheron (France) 627,473 October 5, I927 Hopp et al 2,287,428 June 23, 1942 SUMMARY OF THE INVENTION A framed backing panel is provided with opposed, vertically spaced groove means which respectively receive the upper and lower edges of character plates. The distance between the bases of the upper and lower groove means is sufficiently greater than the height of the character plates, that when any character plate is raised to abut the base of the upper groove, the lower edge of that character plate will clear the lip of the lower groove, whereupon the character plate may be removed from the sign. To prevent unauthorized removal of character plates, an unobstrusive locking strip is longitudinally removably disposed in the upper groove between the base and the upper edges of the character plates. Means may be provided to prevent removal of the locking strip. The panel frame is preferably T-slotted to provide a convenient fastener mount for mounting the sign.

The principles of the invention will be further hereinafter discussed with reference to the drawings wherein preferred embodiments are shown. The specifics illus trated in the drawings are intended to exemplify, rather than limit, aspects of the invention as defined in the claims.

In the drawings:

FIG. 1 is a front elevation view of the sign;

FIG. 2 is an end elevation view of the sign;

FIG. 3 is a fragmentary horizontal sectional view of the sign frame along the line 3-3 of FIG. 1 showing attachment of the sign frame to a standard;

FIG. 4 is a fragmentary vertical sectional view taken substantially along line 4-4 of FIG. 1 showing the relation of the groove means to the character plates, the backing member and the locking strip; and

FIGS. 5-9 are exploded perspective views of alternative means for securing and/or retrieving the locking strip from the groove means.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS In FIG. 1 there is shown a sign 10 which includes a backing panel 12 completely surrounded by a frame 14. The exterior periphery of the frame 14 is provided with an outwardly-facing undercut, e.g. T-shaped, groove 16 which may receive the nut, bolt head 18 or the like of a fastener element which may be used with a cooperating element 20 to secure the respective side of the sign to a standard 22. The example depicted is illustrative of several alternatives which should not be apparent to those skilled in the art. The enlarged fastener element 18 is slidably received in the enlarged cross bar portion 24 of the T-shaped groove through appropriate slot means cut in the frame at one or more points, or through one exposed end of a frame side extrusion before the four mitered sides of the frame are conventionally secured together. This provides an attractive, relatively hidden and adaptable sign mount- There are a plurality of channel members 28 secured on the visible face 30 of the sign backing member. (Where both faces are to be exposed, a similar layout of channel members may be provided on the opposite face of the backing member.)

The channel members 28 proceed generally horizontally across the face 30 with appropriate vertical spacing to define a plurality of vertically spaced character rows. Fastening means such as rivets 32 secure the channel members 28 to the backing member.

With attention to FIG. 4, the channel member 28 illustrated includes an intermediate, rearmost vertical portion 34 through which the rivets 32 pass and which is presented flatwise against the face 30. (However, the face 30 is not necessarily flat; it may, e.g., be fluted, as illustrated in the aforementioned U.S. Pat. No. 3,407,525.)

Above the portion 34, the channel member 28 extends forwardly, then upwardly, then rearwardly not quite so far as it extends forwardly, to define an upwardly opening groove 36 having a lip 38 and a floor 40. For all but the uppermost channel member 28 on a sign, the groove 36 is the lower groove of a character row. For the uppermost channel member 28, the groove 36 may be present but is not usually used.

Below the portion 34, the channel member 28 extends forwardly, then downwardly, then rearwardly not quite so far as it extended forwardly, to define a downwardly opening groove 42 having a lip 44. Intermediate the vertical extent thereof, the downwardly opening groove is internally provided with an internal ledge 46 which restricts the thickness of the groove 42 at that level about as mucnh as the lip 44 does at its level. For all but the lowermost channel member 28 on a sign, the ledge 46 defines the floor of the locking strip receiving compartment 48 of the groove 42. For the lowermost channel member 28, the groove 42 may be present, but is not usually used. 7

Each two vertically adjacent channel members 28 may receive a row of character plates 50 between them. Suitable character plates are described in US. Pat. No. 3,407,525.

When the character plates are received between the grooves of two vertically adjacent channel members, their lower edges rest on the floor 40 of the lower groove 36, and their upper edge regions pass the lip 44 of the upper groove and are disposed within the upper groove 42 below the ledge 46. Although the character plates are horizontally slidable while resting on the floor 40, either the frame 14 is so close to the ends of the channels 28 that the character plates cannot be longitudinally slid out of the grooves, or else the ends of the grooves are obstructed to prevent longitudinal sliding removal of character plates.

The limited permissible sliding of the character plates allows, for instance, an authorized sign changer to put two As side-by-side in a row, then slidingly spread them apart to insert a B to create a row of character plates reading ABA. Likewise, the limited permissible sliding allows the authorized sign changer to center the row of character plates with respect to the sign backing member.

The character plates are installed and removed while the locking strip receiving compartment 48 is empty. To install a character plate, its upper edge region is inserted in the upper, downwardly facing groove while that plates lower edge is held out away from the lower channel 28 of the particular row. The character plate is raised, while being pivoted toward the plane of the face of the sign on which the character plate is being installed, so that the upper edge region of the character plate enters the compartment 48 and the lower edge of the character plate lies above the lip 38 of the upwardly opening groove 36. The character plate is then further rotated toward verticality so the lower edge is disposed above and poised to enter the groove 36, whereupon the character plate is lowered until its lower edge rests on the floor 40. Removal of the character plate involves a reversal of the procedure just described.

It should be apparent that, essential to the installation and removal procedure is the freedom of the character plate upper edges to enter the upper groove sufficiently to clear the lip of the lower groove. In the product depicted, this means that the upper edges of the character plates must be able to enter the compartment region of the upper groove, above the internal ledge 46. Accordingly, installation and removal of the character plates can be prevented so long as the compartment region of the upper groove is obstructed.

In accordance with the principles of the present invention, unauthorized installation and removal of character plates is prevented, or rendered less probable, by providing a locking strip 60 designed to be longitudinally received in the compartment 48. The strip 60 is thicker than a character plate, so it unfailingly rests on the ledge 46, irrespective of whether any character plates are present in the particular row.

For many instances the simplest way to structure and provide the locking strip is to make the strip no longer longitudinally than the channel member 28 in whose compartment 48 it is to be disposed and to make the strip 60 out of somewhat flexible material. Preferably, the strip is so longitudinally long that even if it is slid to one longitudinal extreme, where one end engages the sign frame, its opposite end still protects the opposite end of the compartment 48 to prevent insertion or removal of a character plate there. Due to the preferred flexibility of the strip 60, once one end region has been exposed by longitudinal sliding, the exposed portion may be resiliently warped forwardly so that the exposed end will forwardly clear the frame. Then the strip may be longitudinally withdrawn fully, or at least sufficiently to permit installation and removal of character plates in the manner described above. When such a strip is in place, fully within the compartment 48, it is not casually visible so one who is unaware of its existence and is not methodical in his curiosity or has insufficient time for a complete furtive investigation will be foiled from tampering with the sign. However, one who knows of the locking strip, e.g. an authorized sign changer, will have no trouble pushing it longitudinally from one end, e.g. using an unbent coat hanger or the like, to expose the opposite end for grasping, flexing and withdrawal. When the strip is reinserted its lastexposed end is pushed until it clears the frame, flexes back to a flat condition and enters the compartment 48.

Alternatives for keeping the locking strip in place which require varying, greater degrees of sophistication or ingenuity to foil are shown in FIGS. 5-9. Although in each instance only the left end region of a locking strip and channel member are depicted, it should be realized that the features shown may be provided at either or both ends. A combination of two different forms, one at each end, is also contemplated, as is the combination of a locking strip keeper at one end with extension of the channels to so near the frame at the opposite end that the locking strip can only be withdrawn and inserted from the end provided with the keeping means.

In FIGS. 5 and 5a there is depicted an instance wherein the locking strip 60A is provided at an end with a portion which doubles forward and back over itself a short distance to define a U-shaped clip 62 having an overlying tab 64. The latter is provided with a threaded front-to-back opening 66, which when the strip 60A is fully inserted in the compartment 48, overlies a then coaxial, threaded opening 68 in the front wall of the compartment. A cap screw 70 with socket 72 is threadably received in the aligned openings 66,68. Most people do not carry Allen wrenches with them, so the screw 70 provides a reasonable degree of assuredness that the strip will not be withdrawn by an unauthorized person. The U-shaped clip 62 is shown being a separate part fixedly secured on one end of the locking strip 60A, but it could be formed integrally therewith. Of course, the recess 72 in the cap screw 70 head could be of even more unusual shape, so as to be successfully engageable only with a special tool issued to authorized persons.

In FIG. 6, a vertically-oriented closure bar 74 is provided adjacent one end of the channel member 28. The bar 74 is about as thick as the channel member and substantially as tall. Near one end (e.g. near the lower end as shown) a bolt 76 passes through an opening 78 in the bar, through an aligned opening in the sign backing member and on the opposite face of the sign backing member receives a threaded fastener 80. The bar is thus mounted for pivoting about an axis provided by the shank of the bolt 76. This mounting is illustrative; e.g. a pivot rivet may be substituted for the bolt 76 and nut 80. On a two-faced sign, the pivot may be provided so that it mounts another similar closure bar on the other face of the sign.

The opposite end of the bar 74 is provided with a front to back opening 82 which receives a fastener 84 that releasably secures that end of the bar to the sign backing member. In the instance depicted, the fastener 84 is a cap screw with a recessed head as shown in FIG. 5, and it has been assumed that the sign backing member is made of a soft material (e.g. a sheet of translucent plastic) which would not take a threaded opening which would bear up for the long term. So a small metal plate 86 is secured, e.g. via a rivet 88 to the backing. The plate 86 is provided with a threaded opening for receiving the fastener 84. Accordingly, when the bar is in its working position as shown in full lines, not only can the locking strip not be removed, no character plates can be slid out past the depicted left end of the channel member 28 because the lower end of the bar blocks the left end of the lower character plate row served by the depicted channel member 28 and the upper end of the bar blocks the left end of the upper character plate row (if any) served by the depicted channel member 28.

In the embodiment shown in FIG. 6, a semi-circular cut-out 90 is formed in the left end of the front wall of the compartment so the locking strip may be easily grasped for withdrawal after the bar is freed for pivot- In the modification shown in FIG. 7, a slug 92, e.g. a square of locking strip material, is permanently fastened in the left end of the downwardly opening groove of channel member 28 to prevent character plates from sliding leftwardly thereby. Thus, the slug acts as a stop means; another could be provided at the right end of the channel member. The locking strip 60B is provided with a front-to-back opening 94 that, at the relative longitudinal disposition shown, axially aligns with an opening 96 through the front side of the compartment 48. A cap screw 98 is removably secured through these openings into a threaded opening 100 on a metal plate 102 secured to the sign backing member by a fastener 104 such as a pop rivet. Because of the form and disposition of the keeping means of this embodiment, the locking strip may safely protrude leftwardly of the left end of the channel member 28 so it may be freely grasped for withdrawal after the cap screw has been withdrawn. It should be apparent that this feature could be replaced by the semi-circular cut-out feature depicted in FIG. 6.

In FIG. 8, the locking strip 60C extends leftwardly from the left end of the channel member 28 and is provided with a slot 108 that receives a Ushaped bail 110 secured on a plate 112 which is permanently secured to the sign backing member. The loop of the bail 110 which protrudes forwardly through the slot 108 removably receives the bail 112 of a padlock 1 14 which links therethrough to prevent unauthorized withdrawal of the locking strip. When the strip is to be withdrawn by an authorized sign changer, the lock is unlocked and unlinked from the bail 110. Then the exposed part of the locking strip is flexed forwardly to clear the bail 110, whereupon the strip is free to be withdrawn leftwardly from the compartment 48.

The FIG. 9 embodiment is another simpler example wherein the locking strip 60D is longitudinally short enough to be fully hidden within the compartment 48. However, a front-to-back opening 114 is formed therein near one end thereof so a button hook-like de vice 116 inserted through the related end of the compartment and engaged in the opening 114 facilitates withdrawal of the locking strip. Other permutations of the disclosed examples will now occur to those skilled in the art. For instance, the button hook and opening structure of FIG. 9 could supplement or replace the semi-circular cut-out shown in FIG. 6 or the leftwardly exposed tab of the locking strip of FIG. 7.

It should now be apparent that the sign with changeable character plates as described hereinabove possesses each of the attributes set forth in the specification under the heading Summary of the Invention" hereinbefore. Because the sign with changeable character plates of the invention can be modified to some extent without departing from the principles of the invention as they have been outlined and explained in this specification, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.

What is claimed is: l. A sign for displaying at least one horizontal row of character plates in a manner such that the character plates can be installed, removed and replaced by authorized persons, said sign comprising:

a sign backing member having at least one face; at least two channel members secured on the backing member, one above the other so the channel members proceed horizontally across said face parallel to one another and terminating adjacent the opposite sides of said backing member; the lower channel member having means defining an upwardly opening groove extending therealong, said groove having means defining a lip along the upper extent thereof, said lip being spaced from said face of the backing member by a distance at least equal to the thickness of a character plate adjacent the lower edge of the character plate; the upper channel member having means defining a downwardly opening groove extending therealong, said groove having means defining a lip along the lower extent thereof, said lip being spaced from said face of the backing member by a distance at least equal to the thickness of a character plate adjacent the upper edge of the character plate;

means defining a longitudinally extending ledge within said downwardly opening groove intermediate the height of that groove, said ledge partly constricting said downwardly opening groove but leaving a gap between itself and said face of the backing member at least equal in thickness to the thickness of a character plate adjacent the upper edge of the character plate; said ledge thereby defining a compartment thereabove within said downwardly opening groove;

the distance between the upper and lower channel members being such that a character plate cannot be frontally installed and removed unless the upper edge thereof is permitted to temporarily pass said ledge and enter said compartment so the lower edge of the character plate can clear said lip of the upwardly opening groove;

and a flexible locking strip longitudinally, slidably received in said compartment, said locking strip being thicker than said gap, and said locking strip, when disposed within said compartment obstructing the compartment sufficiently to prevent character plate upper edges from passing said ledge and entering said compartment to an extent sufficient to permit the lower edges of the character plates to clear said lip of the upwardly opening groove, so that character plates may neither be frontally installed nor frontally removed when the locking strip is disposed within the compartment.

2. The sign of claim 2 further comprising:

means preventing longitudinal sliding of character plates from the ends of said upper and lower channel members.

3. The sign of claim 2 wherein said preventing means, for at least one end of each channel member is constituted by framing element means bordering said sign backing member and protruding forwardly of said face, said upper and lower channel members terminating so closely adjacent the framing element means that a character plate being slid longitudinally would abut the framing element means before it was free of said grooves.

4. The sign of claim 3 wherein the opposite end of at least one of said channel members is provided with an obstructing stop obstructing said groove thereof to constitute said preventing means for the opposite ends of said channel members.

5. The sign of claim 3 wherein said backing member is rectangular and said framing element means borders all four sides thereof; said framing element means having means defining an outwardly opening undercut slot therein; said slot receiving at least one fastener element trapped therein; a sign standard; a cooperative securing element cooperating with the fastener element trapped in said slot to secure the framing element means to the sign standard.

6. The sign of claim 2 wherein the locking strip is no longer longitudinally than the compartment so the upper channel member substantially conceals the locking strip.

7. The sign of claim 6 further including means defining an opening through the locking strip near one end thereof, which opening may be snagged by a device such as a button hook in order to longitudinally withdraw the locking strip to a condition of partial exposure where it is free to be grasped and further withdrawn.

8. The sign of claim 2 further including keeper means on the locking strip and on the upper channel member for removably securing the locking strip to the upper channel member to reduce the possibility of unauthorized longitudinal withdrawal of the locking strip from the compartment.

9. The sign of claim 8 wherein the keeper means comprises an opening in the locking strip, an opening in the upper channel member, said openings being axially aligned when the locking strip is in place, and a securing device received through both said openings.

10. The sign of claim 9 wherein the locking strip has means defining a U-shaped clip at one end thereof including a portion which proceeds forwardly then doubles back over the locking strip a short distance to constitute a tab positioned to overlie the compartment at one end of the upper channel member; said opening in said locking strip being disposed in said tab thereof.

11. The sign of claim 2 further including keeper means on the locking strip and on the sign backing member for removably securing the locking strip to the upper channel member to reduce the possibility of unauthorized longitudinal withdrawal of the locking strip from the compartment.

12. The sign of claim 11 wherein the keeper means comprises an opening in the locking strip, a fastener securing on the sign backing member, and a securing device extending through said opening and being secured to said fastener.

13. The sign of claim 11 wherein the keeper means includes a slot formed in the locking strip, a U-shaped bail secured on the sign backing member and looping through the slot; and a padlock including a bail linked through the first-mentioned bail, forwardly of the locking strip.

14. The sign of claim 11 wherein the keeper means includes a keeper bar; means pivotally securing the keeper bar to the sign backing member adjacent one end of the upper channel member; and means for disconnectably fastening the other end of the keeper bar to the sign backing member in a generally vertically extending condition athwart the respective end of the compartment. 

1. A sign for displaying at least one horizontal row of character plates in a manner such that the character plates can be installed, removed and replaced by authorized persons, said sign comprising: a sign backing member having at least one face; at least two channel members secured on the backing member, one above the other so the channel members proceed horizontally across said face parallel to one another and terminating adjacent the opposite sides of said backing member; the lower channel member having means defining an upwardly opening groove extending therealong, said groove having means defIning a lip along the upper extent thereof, said lip being spaced from said face of the backing member by a distance at least equal to the thickness of a character plate adjacent the lower edge of the character plate; the upper channel member having means defining a downwardly opening groove extending therealong, said groove having means defining a lip along the lower extent thereof, said lip being spaced from said face of the backing member by a distance at least equal to the thickness of a character plate adjacent the upper edge of the character plate; means defining a longitudinally extending ledge within said downwardly opening groove intermediate the height of that groove, said ledge partly constricting said downwardly opening groove but leaving a gap between itself and said face of the backing member at least equal in thickness to the thickness of a character plate adjacent the upper edge of the character plate; said ledge thereby defining a compartment thereabove within said downwardly opening groove; the distance between the upper and lower channel members being such that a character plate cannot be frontally installed and removed unless the upper edge thereof is permitted to temporarily pass said ledge and enter said compartment so the lower edge of the character plate can clear said lip of the upwardly opening groove; and a flexible locking strip longitudinally, slidably received in said compartment, said locking strip being thicker than said gap, and said locking strip, when disposed within said compartment obstructing the compartment sufficiently to prevent character plate upper edges from passing said ledge and entering said compartment to an extent sufficient to permit the lower edges of the character plates to clear said lip of the upwardly opening groove, so that character plates may neither be frontally installed nor frontally removed when the locking strip is disposed within the compartment.
 2. The sign of claim 2 further comprising: means preventing longitudinal sliding of character plates from the ends of said upper and lower channel members.
 3. The sign of claim 2 wherein said preventing means, for at least one end of each channel member is constituted by framing element means bordering said sign backing member and protruding forwardly of said face, said upper and lower channel members terminating so closely adjacent the framing element means that a character plate being slid longitudinally would abut the framing element means before it was free of said grooves.
 4. The sign of claim 3 wherein the opposite end of at least one of said channel members is provided with an obstructing stop obstructing said groove thereof to constitute said preventing means for the opposite ends of said channel members.
 5. The sign of claim 3 wherein said backing member is rectangular and said framing element means borders all four sides thereof; said framing element means having means defining an outwardly opening undercut slot therein; said slot receiving at least one fastener element trapped therein; a sign standard; a cooperative securing element cooperating with the fastener element trapped in said slot to secure the framing element means to the sign standard.
 6. The sign of claim 2 wherein the locking strip is no longer longitudinally than the compartment so the upper channel member substantially conceals the locking strip.
 7. The sign of claim 6 further including means defining an opening through the locking strip near one end thereof, which opening may be snagged by a device such as a button hook in order to longitudinally withdraw the locking strip to a condition of partial exposure where it is free to be grasped and further withdrawn.
 8. The sign of claim 2 further including keeper means on the locking strip and on the upper channel member for removably securing the locking strip to the upper channel member to reduce the possibility of unauthorized longitudinal withdrawal of the locking strip from the compartment.
 9. THe sign of claim 8 wherein the keeper means comprises an opening in the locking strip, an opening in the upper channel member, said openings being axially aligned when the locking strip is in place, and a securing device received through both said openings.
 10. The sign of claim 9 wherein the locking strip has means defining a U-shaped clip at one end thereof including a portion which proceeds forwardly then doubles back over the locking strip a short distance to constitute a tab positioned to overlie the compartment at one end of the upper channel member; said opening in said locking strip being disposed in said tab thereof.
 11. The sign of claim 2 further including keeper means on the locking strip and on the sign backing member for removably securing the locking strip to the upper channel member to reduce the possibility of unauthorized longitudinal withdrawal of the locking strip from the compartment.
 12. The sign of claim 11 wherein the keeper means comprises an opening in the locking strip, a fastener securing on the sign backing member, and a securing device extending through said opening and being secured to said fastener.
 13. The sign of claim 11 wherein the keeper means includes a slot formed in the locking strip, a U-shaped bail secured on the sign backing member and looping through the slot; and a padlock including a bail linked through the first-mentioned bail, forwardly of the locking strip.
 14. The sign of claim 11 wherein the keeper means includes a keeper bar; means pivotally securing the keeper bar to the sign backing member adjacent one end of the upper channel member; and means for disconnectably fastening the other end of the keeper bar to the sign backing member in a generally vertically extending condition athwart the respective end of the compartment. 